3 DSS-1 , , . , DSS-1.
, . 4. , 1 1.
. 4. 3 DSS-1
3 : , . , / .
(PD protocol discriminator). DSS-1, ( ), , . ISDN , , Q.931, Frame relay. . , , ISDN , 00001000.
(CR call reference) , , . , , 2. , , .
. 4. , ~ . 1 127, 7 1 2. 0 215-1, .
, . , . , , . , 2 . , : (0) (1). ( , , , 2.)
|
|
. 5
( message type) , , (, SETUP, DISCONNECT ..). , .. :
, . , , SETUP, ( ) ;
, . , , USER IN FORMATION, / -;
( ). , , DISCONNECT, ( ), , ;
, , INFORMATION, ;
00000000, , , .
5. Q.931
:
.
6.
- | ALERTING | |
CALL PROCEEDING | ||
CONNECT | () | |
CONNECT ACKNOWLEDGE | ||
PROGRESS | ||
SETUP | ||
SETUP ACKNOWLEDGE | ||
DISCONNECT | ||
RELEASE | ||
RELEASE COMPLETE | ||
RESTART | ||
RESTART ACKNOWLEDGE | ||
- | RESUME | |
RESUME ACKNOWLEDGE | ||
RESUME REJECT | ||
SUSPEND | ||
SUSPEND ACKNOWLEDGE | ||
SUSPEND REJECT | ||
USER INFORMATON | ||
CONGESTION CONTROL | ||
FACILITY | ||
INFORMATION | ||
STATUS | ||
STATUS ENQUIRY | ||
NOTIFY |
CALL_PROCEEDING. , . SETUP , , , , , .
|
|
CONNECT. , . , , . ANSWER ISUP -7. .7 CONNECT ( , ).
CONNECT_ACKNOWLEDGE. CONNECT.
CONGESTION_CONTROL. USER_IN FORMATION.
7. CONNECT
. | () | ||
³2 | |||
³2 | , . , CONNECT SETUP | ||
- | 2-4 | SETUP | |
2-82 | SETUP | ||
- | 2-131 | "-", |